I've heard that it's forbidden to cross the fingers
of the right hand with the fingers of the left hand. This sounds
a bit baffling. And I see Orthodox Jews who do this and wonder
if they are ignorant of a prohibition or perhaps just not always
aware of the state of their fingers. Thank you for this wonderful
service.

Dear Sherry,

Crossing the fingers isn't really a prohibition,
but it is mentioned in traditional sources as something to avoid.
Here is the explanation of one commentary: "The right side
represents Divine mercy whereas the left represents Divine strict
judgment, and it is inappropriate for a person to do something
that signifies a mixing of these distinct attributes of G-d.
It is even a dangerous thing to do, and therefore one should be
careful to avoid this practice." This is a deep kabbalistic
concept that we cannot truly understand.

I asked a renowned Jerusalem rabbi who said that
if you aren't generally concerned about intertwining your fingers
then there's no need to be concerned about this. Only if one is
generally careful not to cross fingers because of it being
wrong or even dangerous does one need to be always careful
not to do so.